The use of the word hell is actually a whole lot simpler than people here are making it out to be. It's simply the Germanic equivalent of Hades--i.e. an underworld realm where the dead go. So when these things got translated into English, they used their native word. The Greek Hades in the scriptures was itself a translation of the Semitic Sh'ol, which also referred to the underworld. It's simply a case of using different native words to refer to the same basic idea, no vast conspiracy required.
That underworld realm was originally not a place of torment, just a common destination for dead people generally. The idea of lakes of fire and stuff came about later. Sh'ol, Hades, and the Nordic Hel are all cold, dark, subterranean realms. The association with fire mostly comes from people's equating Hades with Gehinnom, a place where trash was burned, but that's not necessarily a legitimate connection in the texts, which refer to them separately and in different contexts.